invalid add name

my add title is "cricut_and-Cutlebug_embossing_machines" when i click on create add a red message comes up saying invalid add name only use alphanumeric or underscore. Taking this message on face value can someone please tell me what is wrong with this add title and how to put it right because however i change it i get same message. I think it is ok but i must be wrong thanks for any sudgestions